Bo Ryan and the Amazing No Foul Defense

10 October 2008

On March 15, 2008, Wisconsin defeated Michigan State by two points in the Big Ten Tournament. This was not a shocking result - both of these teams were very good last season. But the way in which the game unfolded had Spartan fans howling. Wisconsin attempted 37 free throws to MSU's 19. Moreover, Wisconsin attempted 46 field goals to MSU's 50. For those of you scoring at home, that's a Free Throw Rate of 38.0 for MSU, and a rate of 80.4 (!) for Wisconsin. To say it was the difference in the game is an understatement.

But this is nothing new for Bo Ryan's teams at Wisconsin. Ever since Ryan took over in 2001-02, the Badgers have enjoyed a considerable "fouls per game" edge against their conference opponents:

In the last two seasons, this edge has risen from 2-4 fouls per game to 5 fouls per game. And it's not as if the Badgers are drawing fouls at a higher rate - this has stayed relatively constant under Ryan's tenure. No, it's just that the defense has stopped fouling.

One thing that appears relatively clear, however, is that this is not the Kohl Center at work. Ryan's teams draw fouls at a very steady pace throughout the season:

Wisconsin Conference Fouls per Game, 2007-08 season:

But is this a skill Ryan has taught his players, or is it superior advocacy that he brings to the sidelines? To investigate, I've looked at various defensive metrics, to see if the Badgers are making a trade-off here.

Conference Opp. FG Percentage:

Conference Opp. 3P FG Percentage:

Conference Opp. Offensive Rebounding Percentage:

Wisconsin Conf. Block Percentage:

Wisconsin Conf. Steal Percentage:

Conference Opp. TO Percentage:

I have to come clean here. I wanted the numbers to show me something. Specifically, I wanted the numbers to show me some trade-off that Ryan's teams were making, as a cost of not fouling as much. I can believe that Ryan has figured out how to play solid defense without fouling, but it's hard for me to believe that doing so comes at no cost. Of course, that doesn't mean that can't happen. It's entirely possible that Ryan is a defensive genius who has figured out something that other coach has been able to copy...but that doesn't sound very likely. All innovative coaches adopt a strategy at some cost - whether it's the POT ("perimeter oriented team") that has trouble rebounding its misses, or the very tall team that loses guard skills. There's no such thing as a free lunch.

And as I was putting these graphs together, every single one was disappointing and offered no explanation for the foul gap...until I got to the Conference Opponent TO Percentage, the very last graph shown. Opponent TOs have dropped substantially in Ryan's tenure, and that offers up a plausible explanation behind the foul gap. From the looks of it, Ryan's teams do not pressure the opponent into mistakes. Less ball pressure equals less fouls.

Of course, this is far from proof, in either direction. The TO Rate could be a coincidence. No doubt some will note that the TO Rate has reached its highest levels in Ryan's tenure at the same time that the foul gap is the largest. Maybe there is no clean story here, and we go right back to Badger fans singing the praises of Ryan's genius, and the rest of the Big Ten crying foul. We don't really know for sure, but for my money, I'm sticking with the TO theory.